Glass fibers are employed by many photonic designs. In many occasions the glass fiber is configured in a complex three-dimensional arrangement. Unlike copper wires, glass fibers are susceptible to static fatigue (delayed fracture) that eventually leads to fiber breakage. As far as the fiber desirability is concerned, the ability to predict and possibly minimize the fiber curvature for lower induced stresses is of obvious practical importance.
One application that requires fiber bending is the "pigtail" arrangement in a gain equalization filter (GEF) splice box design. Typically, in this arrangement, one end of the fiber is clamped. The fiber axis at this clamped end is parallel to the generating line of the splice box cylinder. The fiber is wrapped around this cylinder, so that its other end touches the inner surface of a flange fastened on the cylinder. The free end of the fiber is oriented along the cylinder circumference. Thus, there is a need to reduce the stress on a bent fiber so as to extend its life expectancy.